Heat spreader with vapor chamber and method for manufacturing the same

ABSTRACT

The heat spreader includes a flattened casing which defines a vapor chamber therein, a wick structure formed on an inner face of the casing and a supporting frame received in the vapor chamber. The supporting frame includes a plurality of supporting wires. Each of the supporting wires has a column-spiral configuration.

BACKGROUND

1. Technical Field

The disclosure generally relates to heat spreaders and, more particularly, to a heat spreader with a vapor chamber having a supporting frame received in the vapor chamber and a method for manufacturing the heat spreader.

2. Description of Related Art

Electronic components, such as central processing units (CPUs) comprise numerous circuits operating at high speeds and generating substantial heat. Under most circumstances, it is necessary to cool the CPUs to maintain safe operating conditions and assure that the CPUs function properly and reliably. In the past, various approaches have been used to cool electronic components.

A heat spreader with a vapor chamber is usually used to help heat dissipation for electronic components. The heat spreader generally includes a base, a cover mounted on the base and a sealed chamber defined between the base and the cover. Moderate working liquid is contained in the chamber. The base has a wick structure spreading on the whole inner face thereof, and the cover has a wick structure spreading on the whole inner face thereof, too. During operation, the base absorbs heat from an electronic component, and the working liquid is heated into vapor in the chamber. The vapor flows towards the cover and dissipates the heat to the cover, then condenses into liquid and returns back to the base by force (i.e., capillary action) generated by the wick structures to continue a next phase-change cycle.

However, since the heat spreader is a hollow plate-shaped structure, it is prone to be deformed when subjected to a large pressure. Such deformation of the heat spreader may result in the wick structures disengaged from the inner faces of the heat spreader, thus adversely affecting heat transfer efficiency of the heat spreader.

What is needed, therefore, is a heat spreader with a vapor chamber which can overcome the above problems.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an assembled, isometric view of a heat spreader in accordance with a first embodiment of the disclosure, with a heat sink positioned thereon and an electronic component positioned therebelow.

FIG. 2 is a cross-sectional view of FIG. 1, taken along a line II-II thereof.

FIG. 3 is a schematic, top view of a supporting frame of the heat spreader of FIG. 1.

FIG. 4 is an isometric view of a supporting wire of the supporting frame of FIG. 3.

FIG. 5A is a schematic, top view of a supporting frame of the heat spreader in accordance with a second embodiment of the disclosure.

FIG. 5B is a schematic, top view of a supporting frame of the heat spreader in accordance with a third embodiment of the disclosure.

FIG. 5C is a schematic, top view of a supporting frame of the heat spreader in accordance with a fourth embodiment of the disclosure.

FIG. 5D is a schematic, top view of a supporting frame of the heat spreader in accordance with a fifth embodiment of the disclosure.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, a heat spreader 10 in accordance with a first embodiment of the disclosure absorbs heat generated by an electronic component 20 mounted below the heat spreader 10. Typically, a finned metal heat sink 30 is attached to a top face of the heat spreader 10 to remove the heat therefrom. The heat absorbed by the heat sink 30 is then dissipated to ambient air.

The heat spreader 10 comprises a hollow casing 11 which defines a vapor chamber 12 therein, a wick structure 13 formed on an inner face of the casing 11, and a supporting frame 14 received in the vapor chamber 12. A predetermined quantity of working liquid, such as water, alcohol, olefin and so on, is contained in the vapor chamber 12 for transferring heat by phase change. The vapor chamber 12 is evacuated for facilitating evaporation of the working liquid.

The casing 11 is a hollow rectangular plate and integrally made of a metal with good heat conductivity, such as aluminum, copper, or an alloy thereof. The casing 11 comprises a base 15 thermally attached to the electronic component 20 and a cover 16 located above and parallel to the base 15. The heat sink 30 is thermally disposed on the cover 16.

The wick structure 13 spreads on the whole inner face of the casing 11 and surrounds the vapor chamber 12. The wick structure 13 can be selected from some suitable materials, such as sintered metal powder, metal mesh, carbon nanotube array, bundle of fibers and so on.

Referring to FIGS. 3-4 also, the supporting frame 14 is horizontally sandwiched between the base 15 and the cover 16 of the casing 11, and comprises a plurality of supporting wires 142 interlaced with each other. Each of the supporting wires 142 has a column-spiral configuration similar to a spring. An axis of each supporting wire 142 is parallel to the base 15 and the cover 16 of the casing 11. Opposite bottom and top sides of each supporting wire 142 are attached to the wick structure 13 formed on the base 15 and the cover 16, respectively. The supporting wires 142 comprise a plurality of first supporting wires 1420 and a plurality of second supporting wires 1422. The first supporting wires 1420 are parallel to and spaced from each other. The second supporting wires 1422 are parallel to and spaced from each other, and perpendicular to the first supporting wires 1420. The first supporting wires 1420 are coplanar and crisscross with the second supporting wires 1422. Thereby, the supporting frame 14 is configured as a mesh having a plurality of openings between the supporting wires 142.

Referring to FIG. 5A through FIG. 5D also, it can be understood that the supporting wires 142 can be arranged in different manners; that is to say, a structure of the supporting frame 14 is variable. In a second embodiment of the present disclosure, schematically as shown in FIG. 5A, the supporting frame 14 a comprises a plurality of supporting wires 142 a, wherein the supporting wires 142 a are all parallel to and spaced from each other.

In a third embodiment of the present disclosure, as schematically shown in FIG. 5B, the supporting frame 14 b comprises a plurality of supporting wires 142 b, wherein the supporting wires 142 b are located adjacent to each other, with wave troughs of an upper supporting wire 142 b engaging with respective wave crests of a lower supporting wire 142 b.

In a fourth embodiment of the present disclosure, as schematically shown in FIG. 5C, the supporting frame 14 c comprises a plurality of supporting wires 142 c connecting with each other end-to-end and in series to have a configuration of a zigzag. Every two adjacent supporting wires 142 c define an acute angle therebetween. The acute angles are alternately located at opposite sides of the supporting frame 14 c as viewed from FIG. 5C.

In a fifth embodiment of the present disclosure, as schematically shown in FIG. 5D, the supporting frame 14 d comprises a plurality of supporting wires 142 d connecting with each other end-to-end and in series to have a configuration of a rectangular vortex, wherein every two adjacent two supporting wires 142 d define a right angle therebetween. The supporting frame 14 d integrally extends along the rectangular vortex from a periphery gradually toward a center of the vapor chamber 12. The supporting wires 142, 142 a, 142 b, 142 c, 142 d have similar configurations, with different lengths.

A method for manufacturing the heat spreader 10 of the disclosure comprises steps described below. Firstly, a metallic elongated and flat tube is provided. The tube is then cut into a plurality of similar semifinished parts each having a predetermined length in order to form the casing 11, wherein each semifinished part has two openings at two opposite sides thereof. An insert (not shown) is inserted into the semifinished part through one of the openings thereof, with a gap defined between the insert and top and bottom of the semifinished part. Metal powder is then filled into the gap between the insert and the semifinished part and then sintered onto the inner face of the semifinished part by heating the metal powder, to thereby form the wick structure 13 over the inner face of the semifinished part. The insert according to the preferred embodiment is a solid metallic block which is withdrawn from the semifinished part after the powder is sintered onto the inner face of the semifinished part. Alternatively, the insert can be a hollow block formed by woven meshes which is able to be sintered onto the inner face of the semifinished part as a part of the wick structure 13 when sintering the powder. Thereafter, the supporting frame 14 is placed into the semifinished part. The two opposite sides of the semifinished part are punched to be sealed for sealing the vapor chamber 12, in which an injection hole is formed in one of the two sealed opposite sides so that work liquid can be injected into the vapor chamber 12 via the injection hole and the vapor chamber can be vacuumed via the injection hole. Finally, the injection hole is sealed, whereby the housing 11 is formed by the semifinished part and the manufacturing of the heat spreader 10 is finished, which incorporates the supporting frame 14 therein.

During use of the heat spreader 10, the electronic component 20 is attached to the base 15, and the base 15 absorbs the heat produced by the electronic component 20. The working liquid saturated in the wick structure 13 formed on the base 15 is heated into vapor. The vapor is quickly diffused into the whole vapor chamber 12 of the heat spreader 10. When the vapor contacts the wick structure 13 formed on the cover 16 and the cover 16, it gives out heat and condenses into liquid. The condensed working liquid then flows back to the base 15 through the wick structure 13. The supporting frame 14 which is received in the vapor chamber 12 prevents the casing 11 from being deformed when the casing 11 is subject to pressure acting thereon.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set fourth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat spreader comprising: a casing defining a vapor chamber therein; a working liquid contained in the vapor chamber; a wick structure formed on an inner face of the casing and correspondingly surrounding the vapor chamber; and a supporting frame received in the vapor chamber and comprising a plurality of supporting wires, and each of the supporting wires having a column-spiral configuration.
 2. The heat spreader as claimed in claim 1, wherein each of the supporting wires is an elongated spring.
 3. The heat spreader as claimed in claim 1, wherein the supporting wires are disposed horizontally in the vapor chamber.
 4. The heat spreader as claimed in claim 1, wherein the supporting wires comprise a plurality of first supporting wires and a plurality of second supporting wires interlacing with the first supporting wires.
 5. The heat spreader as claimed in claim 4, wherein the first supporting wires crisscross with the second supporting wires.
 6. The heat spreader as claimed in claim 1, wherein the casing is plate-shaped and comprises a base and a cover located above the base, the supporting wires are sandwiched between the base and the cover.
 7. The heat spreader as claimed in claim 1, wherein the supporting wires are spaced from and parallel to each other.
 8. The heat spreader as claimed in claim 1, wherein wave troughs of an upper one of the supporting wires engage with respective wave crests of an adjacent lower one of the supporting wires.
 9. The heat spreader as claimed in claim 1, wherein the supporting wires connect with each other to form a zigzag configuration.
 10. The heat spreader as claimed in claim 1, wherein the supporting wires connect with each other to have a configuration of a rectangular vortex, which extends from a circumference of the vapor chamber gradually to a center of the vapor chamber.
 11. A method for manufacturing a heat spreader comprising: providing a flattened casing defining a vapor chamber therein and having at least an opening in a side thereof, forming a wick structure on an inner face of the casing; providing a supporting frame comprising a plurality of supporting wires, and each of the supporting wires having a column-spiral configuration; placing the supporting frame into the casing; and injecting working liquid into the vapor chamber and sealing the casing.
 12. The method as claimed in claim 11, wherein the supporting wires are disposed horizontally in the vapor chamber.
 13. The method as claimed in claim 11, wherein the supporting wires comprise a plurality of first supporting wires and a plurality of second supporting wires interlacing with the first supporting wires.
 14. The method as claimed in claim 11, wherein wave troughs of an upper one of the supporting wires engage with respective wave crests of an adjacent lower one of the supporting wires.
 15. The method as claimed in claim 11, wherein the supporting frame integrally extends along a zigzag line.
 16. The method as claimed in claim 11, wherein the supporting frame integrally extends along a vortex from a circumference of the vapor chamber gradually to a center of the vapor chamber. 